@article{ZhouLauwaetHooyberghsetal.2016,
  author    = {Zhou, Bin and Lauwaet, Dirk and Hooyberghs, Hans and De Ridder, Koen and Kropp, J{\"u}rgen and Rybski, Diego},
  title     = {Assessing Seasonality in the Surface Urban Heat Island of London},
  series = {Journal of applied meteorology and climatology},
  volume    = {55},
  journal   = {Journal of applied meteorology and climatology},
  publisher = {American Meteorological Soc.},
  address   = {Boston},
  issn      = {1558-8424},
  doi       = {10.1175/JAMC-D-15-0041.1},
  pages     = {493 -- 505},
  year      = {2016},
  abstract  = {This paper assesses the seasonality of the urban heat island (UHI) effect in the Greater London area (United Kingdom). Combining satellite-based observations and urban boundary layer climate modeling with the UrbClim model, the authors are able to address the seasonality of UHI intensity, on the basis of both land surface temperature (LST) and 2-m air temperature, for four individual times of the day (0130, 1030, 1330, and 2230 local time) and the daily means derived from them. An objective of this paper is to investigate whether the UHI intensities that are based on both quantities exhibit a similar hysteresis-like trajectory that is observed for LST when plotting the UHI intensity against the background temperature. The results show that the UrbClim model can satisfactorily reproduce both the observed urban rural LSTs and 2-m air temperatures as well as their differences and the hysteresis in the surface UHI. The hysteresis-like seasonality is largely absent in both the observed and modeled 2-m air temperatures, however. A sensitivity simulation of the UHI intensity to incoming solar radiation suggests that the hysteresis of the LST can mainly be attributed to the seasonal variation in incoming solar radiation.},
  language  = {en}
}
@article{FluschnikKriewaldRosetal.2016,
  author    = {Fluschnik, Till and Kriewald, Steffen and Ros, Anselmo Garcia Cantu and Zhou, Bin and Reusser, Dominik Edwin and Kropp, J{\"u}rgen and Rybski, Diego},
  title     = {The Size Distribution, Scaling Properties and Spatial Organization of Urban Clusters: A Global and Regional Percolation Perspective},
  series = {ISPRS International Journal of Geo-Information},
  volume    = {5},
  journal   = {ISPRS International Journal of Geo-Information},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2220-9964},
  doi       = {10.3390/ijgi5070110},
  pages     = {1543 -- 1559},
  year      = {2016},
  abstract  = {Human development has far-reaching impacts on the surface of the globe. The transformation of natural land cover occurs in different forms, and urban growth is one of the most eminent transformative processes. We analyze global land cover data and extract cities as defined by maximally connected urban clusters. The analysis of the city size distribution for all cities on the globe confirms Zipf's law. Moreover, by investigating the percolation properties of the clustering of urban areas we assess the closeness to criticality for various countries. At the critical thresholds, the urban land cover of the countries undergoes a transition from separated clusters to a gigantic component on the country scale. We study the Zipf-exponents as a function of the closeness to percolation and find a systematic dependence, which could be the reason for deviating exponents reported in the literature. Moreover, we investigate the average size of the clusters as a function of the proximity to percolation and find country specific behavior. By relating the standard deviation and the average of cluster sizes—analogous to Taylor's law—we suggest an alternative way to identify the percolation transition. We calculate spatial correlations of the urban land cover and find long-range correlations. Finally, by relating the areas of cities with population figures we address the global aspect of the allometry of cities, finding an exponent \&\#948; \&\#8776; 0.85, i.e., large cities have lower densities.},
  language  = {en}
}